One of the benefits of using charcoal as a springtail culture substrate is the ease in removing springtails from the culture. Springtails tend to float, while saturated charcoal does not. Add additional distilled, dechlorinated, or reverse osmosis water to the springtail culture, and simply pour out the springtails directly into the vivarium. It’s that simple, and a lot less of a hassle than other methods.
Due to their small size, springtails do not break the surface tension of the water, and therefore float, making it easy to pour springtails out of a culture with a charcoal substrate.